Experiments are directed towards establishing whether aged mice are deficient in their ability to form long-term memory and whether administration of hormones and neuropeptides can retard forgetting in both young-mature and aged mice. The proposed studies will attempt to determine whether aged mice forget more rapidly than young mice when degree of learning is controlled for. Substances such as ACTH and vasopressin have been implicated in the memory fixation process. An impaired ability of old mice to form durable long-term memory may be due to a diminished ability to synthesize and/or secrete hormones. Thus, the administration of hormones may enhance memory consolidation. Experiments are designed to examine the anterograde and retrograde effects of parental and central hormone injections on forgetting in both old and young mice. Aside from determining the temporal features of hormone-induced memory enhancement, we plan to use local injections to determine which brain sites mediate hormone-induced memory facilitation, and whether hormones enhance memory by stimulating protein synthesis.